Fluorine containing cyanopyridines

ABSTRACT

THE PRESENT INVENTION IS DIRECTED TO NEW AND NOVEL CYCANOFLUOROPYRIDINE COMPOUNDS AND TO METHOD EMPLOYING AND COMPOSITIONS CONTAINING THOSE COMPOUNDS AS PESTICIDAL CONSTITUENTS REPRESENTATIVE NEW COMPOUNDS ARE 3,5DICHLORO-4,6-DIFLUOROPICOLINONITRILE AND TETRAFLUOROPICOLINONITRILE, THESE AND OTHER COMPOUNDS OF THE INVENTION BEING PARTICULARLY WELL DAPTED TO BE USED AS SOILD FUMIGANTS FOR THE CONTROL OF SOIL-INFECTING FUNGI.

United States Patent O 3,803,159 FLUORINE CONTAINING CYANOPYRIDINESFlorence E. Torba, Clayton, Calif., assignor to The Dow ChemicalCompany, Midland, Mich. No Drawing. Original application Dec. 26, 1967,Ser. No. 693,105, now Patent No. 3,629,424, dated Dec. 21, 1971. Dividedand this application Mar. 5, 1971, Ser.

Int. Cl. C0741 31/46 US. Cl. 260-2943 Claims ABSTRACT OF THE DISCLOSURECROSS REFERENCE TO RELATED APPLICATION This application is a division ofmy co-pending application Ser. No. 693,105, filed Dec. 26, 1967, now US.Pat. 3,629,424, issued Dec. 21, 1971.

BACKGROUND OF THE INVENTION The cyanofluoropyridine compounds of thisinvention are related to the cyanotetrachloropyridine compoundstetrachloropicolinonitrile, tetrachloronicotinonitrile andtetrachloroisonicotinonitrile, and are preferably prepared therefrom byreaction with potassium fluoride. These tetrachloro starting compoundsare taught in the art and are known to be relatively stable,non-volatile chemicals which have appreciable activity againstsoil-dwelling fungi. However, the cost of treating soil therewith isrelatively high since not only are relatively large dosages of thesechemicals required for effective fungi control, but also the cost ofintroducing the same into the soil with the requisite degree ofuniformity is undesirably large. Thus, the compounds are capable ofperforming the desired fungicidal function only when carefully workedinto the seed bed so as to insure that each soil particle bears aneffective amount of the toxicant.

The present invention rests in part on the discovery of novelcyanofluoropyridine compounds disclosed herein, which have utility for avariety of pesticidal applications. It also rests on the discovery thatthese novel compounds have higher than expected activity against soilfungi even when present in the soil in unusually small amounts, andthat, moreover, this result is obtained when the uniformity of mixturethereof with the soil is substantially less complete than is required bythe corresponding tetrachloro starting materials.

SUMMARY OF THE INVENTION The new and novel compounds of the presentinvention are cyanofluoropyridines having the structure CN FD Cll-nwherein n is an integer having a value of 1 to 4, inclusive. Thosecompounds wherein the cyano group is in the 2- position of the ring aretermed picolinonitriles, while those with the cyano group in the 3- or4-positions are termed nicotinonitriles and isonicotinonitriles,respectively. However, these various groups of compounds will begenerically referred to herein as cyanofluoropyridines, a

3,803,159 Patented Apr. 9, 1974 term which includes those compoundswhich are substituted only by fluorine atoms, as Well as those which aresubstituted by both fluorine and chlorine atoms.

The following compounds are representative of those which fall withinthe scope of the present invention:

tetrafluoropicolinonitrile, 3-chloro-4,5,6-trifluoropicolinonitrile,5-chloro-3,4,6-trifluoropicolinonitrile,6-chloro-3,4,S-trifluoropicolinonitrile,3,5-dichloro-4,6-difluoropicolinonitrile, 3,5,6-trichloro-4-fluoropicolinonitrile,3,4,5-trichloro-6-fluoropicolinonitrile,3,4,6-trichloro-5-fluoropicolinonitrile, tetrafluoronicotinonitrile,5-chloro-2,4,6-trifluoronicotinonitrile,5,6-dichloro-Z,4-difluoronicotinonitrile, 2,5,6-trichloro-4-fluoronicotinonitrile,

4,5 ,6-trichloro-2-fluoronicotinonitrile,2,4,5trichloro-6-fluoronicotinonitrile, tetrafluoroisonicotinonitrile,3-chloro-2,5,6-trifluoroisonicotinonitrile,3,5-dichloro-2,6-difluoroisonicotinonitrile,2,3-dichloro-5,6-difluoroisonicotinonitrile,2,3,S-trichloro-6-fiuoroisonicotinonitrile, and2,3,6-trichloro-5-fluoroisonicotinonitrile.

The cyanofluoropyridine compounds of this invention are whitecrystalline or Waxy materials or colorless liquids. They are slightlysoluble in water and are highly soluble in many organic solvents such asacetone, benzene, xylene, toluene, dimethylformamide, ethanol andisopropanol. It is an advantage of the present invention that thecompounds thereof have vapor pressures which are substantially higherthan those of the corresponding cyanotetrachloropyridines, a qualitywhich, coupled with an unexpectedly high level of pesticidal activity,makes them particularly well adapted to be employed as soil fumigants.Thus, it has been found that the herein described cyanofluoropyridineseffectively permeate the soil for varying distances from their point orlocalized zone of application, whereas no such permeation accompaniestreating with the cyanotetrachloropyridine compounds. It is a furtheradvantage that the compounds hereof, while sufficiently active andpersistant to accomplish the desired pesticidal action when added inpesticidally effective amounts, nevertheless dissipate within areasonable length of time and thus do not interfere with good fieldmanagement practices. The compounds of this invention are also usefulfor application to seeds to protect the latter against fungal attack inthe soil, they being used either alone or in conjunction with other seedprotectants such as the various mercurial fungicides. They are alsouseful in the control of bacterial pests, many of the compounds hereofbeing effective against Staphylococcus aureus, for example. Saidcompounds also have nematocidal activity.

The cyanofluoropyridine compounds of the present invention can all beprepared by heating the appropriate 2-, 3- or 4-cyanotetrachloropyridinecompound with potassium fluoride to obtain the desiredcyanofluoropyridine compound along with potassium chloride as aby-product. The preparation of these cyanotetrachloropyridine startingmaterials, along with their characteristics, is taught in US. Pat. No.3,325,503 and involves reacting chlorine been had with an excess ofpotassium fiuoride of at least 100 mole percent. The reaction conditionsto be employed are not critical. It has been found that the desiredhalogen exchange reaction takes place over a wide range of temperaturesand at elevated, reduced or ambient pressures. Thus, good results havebeen obtained with temperatures ranging from about 40 C. to at leastabout 450 C. Ambient pressures have been employed with good results, ashave the somewhat super-atmospheric pressures induced as the reactantsare heated to relatively higher temperatures in a sealed pressurevessel. Reaction times vary from /2 hour to periods extending over 20hours or more. The reaction proceeds in either the presence or theabsence of an organic solvent which is inert under the reactionconditions employed. Representative inert organic solvents which may beused for this purpose include acetonitrile, dimethylsulfoxide,dimethylformamide, N-methyl-Z-pyrrolidone, sulfolane anddimethylsulfone. A solvent of this type is employed in those reactionswhich are conducted below about l381$0 C. (the melting point range ofthe several 2-, 3- and 4-cyanotetrachloropyridine starting materials) soas to ensure the presence of a reaction mixture which is at leastpartially liquid. The solvent may also be employed in preparationsconducted at higher temperatures. The fluoro-substitution reactionprogresses with time, and the build up of cyanofluoropyridine productsin the reaction mixture can be followed by vapor phase chromatography orother convenient analytical method as the reaction progresses.

Each of the product compounds formed during the reaction can beseparated and obtained in any desired degree of purity by the practiceof conventional procedures known to those skilled in the art. Included,for example, are such methods as filtration, fractional distillation,fractional crystallization, solvent extraction and the like. Moreover,the product compounds can all be identified by a practice of knownanalytical methods and procedures. Among those employed for this purposeare vapor phase chromatography, nuclear magnetic resonance, infra redspectrum, elemental analysis and mass spectrography.

In carrying out the method of this invention, the undesirable fungi canbe controlled by contacting the fungal organisms and/or their habitatwith a fungicidal amount of the cyanofiuoropyridine. When employed inthe treatment of soil, such practice conrols the soil dwelling fungiwhich attack the underground portions of plants such as roots andtubers. Thus, the new practice improves the emergence and growth ofseedlings and the crop harvest.

The distribution of at least a minimum effective dosage of thecyanofluoropyridine compounds in soil is critical and essential to apractice of the soil treating method of the present invention. Indetermining an effective dosage of the soil treating compounds, at leasta fungicidal amount of the desired toxicant should be employed. Ingeneral, good controls of fungi are obtained when the compounds aredistributed in the soil in the amount of from about 0.1 to 50 parts ormore by weight per million parts by weight of soil. However, theeffective amount of the compound to be employed will vary somewhataccording to the particular compound and the nature and condition of thesoil to be treated.

In field applications, the cyanofluoropyridine compounds may bedistributed in the soil by broadcast methods wherein the entire field istreated, or in row applications wherein only the row area to be plantedis treated. In broadcast methods, the compounds can be distributed at adosage of 1 ounce to 400 pounds per acre. Such dosages areconventionally employed through a crosssection of the soil so as toprovide for the presence therein of an efiective concentration of thetreating agent to a depth of at least 2 inches. On the other hand, forsome applications the treated depth may well be 25 inches or more. Inother applications, the cyanofiuoropyridine compounds can be distributedin the ro s Where the p is to be planted. In such row treatment thecyanofiuoropyridine compounds can be employed at a rate of from about0.1 ounce to about 40 pounds per acre. In field application any of theconventional methods such as drenching, drilling, row placement, etc.may be used to distribute the chemical in the soil at a dosage of 0.1 to50 parts for each million parts by weight of the soil actually treatedto produce effective control of fungal and certain bacterial soil pests.This does not, however, limit the application method to thoseconventionally practiced.

The method of the present invention may be carried out by distributingthe unmodified cyanofluoropyridine compound in growth media as byimpregnating or fumigating the soil. However, the present method alsoembraces the employment of liquid or dust compositions containing thetoxicant to effect such impregnation or fumigation. In such usage, thetoxicant compounds hereof may be modified with one or a plurality ofadditaments or soil treating adjuvants including water, organicsolvents, petroleum oils, distillates or naphthas or other liquidcarriers, polymeric thickening agents, urea, surface-active dispersingagents and finely divided inert solids. They also can be employed incompositions containing other pesticides, more especially fungicides,nematocides or insecticides or the like. Depending upon theconcentration of the toxicant, such augmented compositions are adaptedto be distributed in soil or to be employed as concentrates andsubsequently diluted with additional inert carrier to produce theultimate treating compositions. In compositions where the adjuvant is afinely divided solid, a surface active agent or the combination of asurface active agent and a liquid additament, the adjuvant cooperateswith the active component so as to facilitate the invention and obtainan improved and outstanding result.

The exact concentration of the cyanofluoropyridine compounds to beempolyed in the treating composition is not critical and may varyconsiderably provided the required effective dosage of toxicant issupplied in the growth medium. The concentration of toxicant in organicsolvent compositions employed to supply the desired dosage generally isfrom about 10 to percent by weight. With aqueous compositions, therequired dosage is generally supplied with compositions containing from0.2 to 50 percent by weight, although concentrations of 0.0001 percentby weight conveniently may be employed in irrigation treatments of soil.In dusts, the concentration of toxicant may be from about 1 to 50percent by Weight, although concentrations as low as 0.1 percent byweight are sometimes employed. In compositions to be employed asconcentrates, the toxicants may be present in a concentration of from 5to percent by weight.

The quantity of treating composition to be applied may vary considerablyprovided that the required dosage of active ingredient is applied tofacilitate the penetration and distribution of said ingredient in growthmedia. The required amount of the active ingredient in the soil per acretreated may conveniently be supplied in from 1 pint to 20 gallons ormore of the liquid carrier as dispersed in 6 or more acre inches ofirrigation water, or in from 50 to 2,000 pounds of inert solid carrier.In any event a quantity of chemical is applied such as to produce abeneficial concentration in the quantity of soil treated.

Liquid compositions containing the desired amount of active ingredientmay be prepared by dissolving the toxicants in an organic liquid carrieror by dispersing the toxicant in water with the aid of a suitablesurface-active dispersing agent such as in ionic or non-ionicemulsifying agent, the latter also being used, if desired, when anorganic solvent is employed. The surface-active dispersing agents aregenerally employed in the amount of from 1 to 20 percent by weight ofthe combined weight of the cyanofluoropyridine compound andsurface-active agent in the composition. Suitable organic liquidcarriers include acetone, xylene, toluene, isopropanol, polyglycols,chlorinated yd ocarbo s such as me y e chlorid carbon tetrachloride andchlorobenzene and the petroleum distillates such as diesel fuel,kerosene, fuel oil, naphthas, and Stoddard solvent. Among the latter,the petroleum distillates boiling almost entirely under 400 F. atatmospheric pressure and having a flash point above 80 F. are generallypreferred; however, any suitable liquid carrier or combination ofcarriers can be employed.

The aqueous compositions to be employed in the present method maycontain a small amount of a waterimmiscible solvent for the toxicantingredient. In such composition, the carrier comprises an aqueousemulsion, namely, a mixture of water, emulsifying agent and organicliquid. The choice of dispersing and emulsifying agent and the amountthereof employed is dictated by the nature of the composition and by theability of the agent to facilitate the dispersion of the toxicantcompound in the aqueous carrier to produce the desired composition.Dispersing and emulsifying agents which may be employed in thecompositions include the condensation products of alkylene oxides withphenols and organic acids, alkyl aryl sulfonates, polyoxyethylenederivatives of sorbitan esters, complex ether alcohols, mahogany soapsand the like.

In the preparation of dust compositions, the active ingredient isdispersed in and on a finely divided inert solid such as clay, talc,chalk, gypsum, pyrophyllite and the like. In such operations, and finelydivided carrier is mechanically mixed or ground with thecyanofluoropyridine. Similarly, dust compositions containing thetoxicant compounds may be prepared from various solid surface-activedispersing agents such as bentonite, fullers earth, attapulgite andother clays. Depending upon the proportions of ingredients, these dustcompositions may be employed as concentrates and subsequently dilutedwith additional solids, surface-active dispersing agents or with chalk,talc or gypsum and the like to obtain the desired amount of activeingredient in a composition adapted to be employed for the treatment ofsoil. Also, such dust compositions may be dispersed in water with orwithout the aid of a dispersing agent to form spray mixtures.

When operating in accordance with the present invention, thecyanofiuoropyridine compound is dispersed in soil or growth media in anyconvenient fashion, e.g., by simply mixing with the soil, by applying tothe surface of the soil and thereafter dragging or disking into the soilto the desired depth, by employing a liquid carrier to accomplish thepenetration and impregnation, or by injection or drilling techniqueswhereby the toxicant is deposited beneath the surface of the soil. In afurther method, the distribution of the cyanofiuoropyridine compound insoil may be accomplished by dispersing the toxicants in the wateremployed to irrigate the soil. In such procedures, the amount of watermay be varied with the porosity and water-holding capacity of the soilto obtain the desired depth of distribution of the toxicants.

It is a particular feature of this invention that once the toxicant hasbeen introduced into the soil, it is not necessary to blanket the soilto suppress volatilization of the cyanofluoropyridine fumiganttherefrom. Surprisingly, the volatility of the latter compounds is suchas to permit of controlled diffusion thereof through the soil withoutsuffering an unduly rapid loss of the fumigant to the atmosphere beforethe desired fungicidal action takes place. Moreover, when employed inthe herein defined amounts, the toxicant compounds and compositions ofthe present invention have no undesirable seedicidal effect. Thus,seeding of the soil may take place as the fumigant composition hereof isapplied, or at any reasonable time thereafter, e.g. within one or twomonths in most instances, with resultant improvements in the emergenceand growth of seedlings and the crop.

harvest.

A preferred group of soil fungicidal fumigants is that which is made upof the cyanofluoropyridine compounds and compositions containing thesame, as disclosed herein, wherein the cyano group is attached at the2-position of the pyridine ring. The preferred compounds of the presentinvention may be represented by the formula:

wherein n is an integer of from 1 to 4 inclusive. Representativecompounds falling within this preferred group include:

3,5 ,6-trichloro-4-fluoropicolinonitrile, 3,4,5-trichloro-6-fluoropicolinonitrile,3,4,fi-trichloro-S-fluoropicolinonitrile,3,5-dichloro-4,6-difluoropicolinonitrile,3-chloro-4,5,6-trifluoropicolinonitrile,5-chloro-3,4,6-trifluoropicolinonitrile,6-chloro-3,4,S-trifiuoropicolinonitrile, and tetrafiuoropicolinonitrileDESCRIPTION OF THE PREFERRED EMBODIMENTS The following examplesillustrate the invention but are not to be construed as limiting.

Example 1.Tetrafluoropicolinonitrile Tetrachloropicolinonitrile (150grams; 0.621 mole) and potassium fluoride (361 grams; 6.21 moles) arereacted with stirring at 125 C. for 12% hours in the presence of 350milliliters of dimethylformamide; about three-quarters of the potassiumfluoride is added at the beginning of the heating period and the balanceis added after three hours of reaction time. The buildup of products isfollowed by vapor phase chromatography analysis and the final product isfound to contain 86 percent tetrafluoropicolinonitrile and 14 percentchlorotrifluo-ropicolinonitrile isomers. The reaction mixture on beingcooled is filtered to remove salts, and the filtrate is diluted withwater. The dimethylformamide-c-ontaining aqueous phase is extracted withdichloromethane and these extracts are combined with the water-insolublecrude phase. The resulting dichloromethane solution is concentrated bydistillation and rewashed with water to remove any remainingdimethylformamide. The washed organic product phase is then dried withsodium sulfate and the solvent distilled off to give '90 grams of crudefluorinated product. (This separatory technique is that which is used inExamples 2 through 9 below.) The crude product is distilled atatmospheric pressure to give 62 grams of tetrafluoropicolinonitrile asthe fraction boiling between 158 and 165 C. This product ischaracterized as a colorless liquid having carbon, nitrogen and fluorinecontents of 40.12, 15.70 and 43.18 percent as compared with theoreticalvalues of 40.92, 15.91 and 43.16 percent, respectively. It is slightlysoluble in water and highly soluble in acetone and benzene. It has avapor pressure of 1.46 mm. Hg at 25 C.

Example 2.-3-chloro-4,5,6-trifluoropicolinonitrileTetrachloropicolinonitrile (150 grams; 0.621 mole) and potassiumfluoride (180 grams; 3.1 moles) are reacted with stirring in thepresence of 180 milliliters of dimethylformamide. The reaction mixtureis maintained at temperatures gradually rising from 50 to C. for thefirst 7 /2 hours, then at approximately C. for the next 4 hours, andfinally at C. for /2 hour; the product is then found to contain 20percent of monochlorotrifluoropicolinonitrile isomers, 60 percent ofdichlorodifluoropicolinonitrile and 13 percent oftrichlorofluoropicolinonitrile isomers. Using the separatory method setforth in Example 1 there is obtained a crude product which is distilledunder reduced pressure to recover a fraction boiling from 8687 C. at 38mm. Hg. This fraction is a colorless liquid which is slightly soluble inwater and highly soluble in acetone and benzene. It has carbon,chlorine, nitrogen and fluorine contents of 37.24, 18.54, 14.58, and29.47 percent as compared with theoretical values of 37.43, 18.42, 14.55and 29.60 percent, respectively. Nuclear magnetic resonance analysisdiscloses it to be essentially 3-chloro-4,5,6-trifiuoropicolinonitrile,with small percentages of the isomers-chloro-3,4,6-trifluoropicolinonitrile and6-chloro-3,4,5-trifluoropicolinonitrile also being present.

Example 3.3,5,6-trichloro-4-fiuoropicolinonitrile From the crudefiuorinated product of Example 2 there is also distilled under reducedpressure a fraction boiling at 143 C. at 38 mm. Hg. This fraction isrecrystallized from hexane to recover a white crystalline product havinga melting point of 74.2-77.2 C. which is slightly soluble in water andhighly soluble in acetone and benzene. The compound has a vapor pressureof 6.5 X mm. Hg at 25 C. It has carbon, chlorine, nitrogen and fluorinecontents of 32.15, 47.41, 12.22 and 8.38 percent as compared withtheoretical values of 31.96, 47.18, 12.43 and 8.43 percent,respectively. Nuclear magnetic resonance analysis discloses that thisproduct is made up essentially of 3,5,6-tricl1loro 4fluoropicolinonitrile with small amounts of the isomers3,4,5-trichloro-6-fiuoropicolinonitrile and3,4,6-trichloro-S-fiuoropicolinonitrile also being present.

Example 4.3,5-dichloro-4,6-difluoropicolinonitrileTetrachloropicolinonitrile (50 grams; 0.207 mole) is reacted withpotassium fluoride (60.2 grams; 1.035 moles) in the presence of 100milliliters of dimethyl-formamide, the reaction mixture being maintainedat 125 C. for 5% hours. At the end of this period vapor phasechromatography discloses that the mixture contains 71 percent ofdichlorodifluoropicolinonitrile, 28 percent ofchlorotrifluoropicolinonitriles and less than 1 percent oftrichlorofluoropicolinonitriles. The reaction mixture is worked up inthe same fashion as described above in Example 1 and distilled underreduced pressure to recover 13.1 grams of a fraction boiling 100 C. at38 mm. Hg. On being recrystallized from hexane, this product isrecovered as a white crystalline material having a melting point of61.8-66.5 C. which nuclear magnetic resonance analysis discloses to beessentially all 3,5-dichloro-4,6- difluoropicolinonitrile. It isslightly soluble in water, highly soluble in acetone and benzene, andhas a vapor pressure of 3.8)(10- mm. Hg at 25 C. It has carbon,chlorine, nitrogen and fluorine contents of 34.2, 33.4, 13.0 and 19.4percent as compared to theoretical values of 34.48, 33.93, 13.41 and18.18 percent, respectively.

Example 5.3,5-dichloro-2,6-difluoroisonicotinonitrileTetrachloroisonicotinonitrile (100 grams; 0.414 mole) and potassiumfluoride (121 grams; 2.07 moles) are reacted together wi-th stirring inthe presence of 200 rnilliliters of dimethylsulfoxide, the reactionbeing conducted at 40-50 C. for 5 hours. The reaction mixture is workedup in the same fashion as described above in Example 1, following whichthe crude fluorinated product is distilled under reduced pressure torecover 30 grams of a fraction boiling at 109-1 13 C. at 38 mm. Hg. Onbeing recrystallized from hexane, this product is recovered asa whitecrystalline material having a melting point of 7678 C. which is slightlysoluble in water and highly soluble in acetone and benzene. It has avapor pressure of 8.4)(10 mm. Hg at 25 C. This product, which nuclearmagnetic resonance discloses to be made up essentially of 3,5-di-*chloro-Z,6-difluoroisonicotinonitrile together with a small percentageof the isomer 2,3dichloro-5,G-difluoroisonicotinonitrile, is found tohave carbon, chlorine, fluorine and nitrogen contents of 34.1, 33.6,18.41 and 13.1 percent as compared with theoretical values of 34.48,33.93, 18.18 and 13.41 percent, respectively.

Example 6.-2,3,S-trichloro-6-fiuoroisonicotinonitrile From the crudefluorinated product described above in Example 5 there is also distilledunder reduced pressure approximately 12 grams of a fraction boiling at142- 144 C. at 38 mm. Hg. This fraction is recrystallized from hexane torecover a White crystalline product having a melting point of 84-87" C.which is slightly soluble in water and highly soluble in acetone andbenzene. Nuclear magnetic resonance analysis discloses it to be made upof 2,3,5-trichloro-6-fluoroisonicotinonitrile together with a minorproportion of the isomer 2,3,6-trichloro-5-fluoroisonicotinonitrile.This product is found to have carbon, chlorine, nitrogen and fluorinecontents of 32.22, 46.88, 12.51 and 7.56 percent as compared totheoretical values of 31.96, 47.18, 12.43 and 8.43 percent,respectively.

Example 7.5-chl0r02,4,6-trifiu0ronic0tinonitrileTetrachloronicotinonitrile (40 grams; 0.165 mole) and potassium fluoride(40 grams; 0.65 mole) are reacted together with stirring in the presenceof 125 milliliters of acetonitrile, the reaction being conducted at C.for 18 hours. This product is found to contain 8% ofmonochlorotrifluoronicotinonitriles, 40% ofdichlorodifiuoronicotinonitriles and 43% oftrichloromonofluoronicotinonitriles. The reaction mixture is worked upin the manner described in Example 1, following which the crudefluorinated product is distilled under reduced pressure to recover5-chloro-2,4,6-trifluoronicotinonitrile as the fraction boiling at 88 C.at 38 mm. Hg. This product is a colorless liquid Which is slightlysoluble in water and highly soluble in acetone and benzene. It hascarbon, chlorine, nitrogen and fluorine contents of 36.05, 17.58, 14.28and 29.77 percent as compared to theoretical values of 37.43, 18.42,14.55 and 29.60 percent, respectively.

Example 8.2,5 dichloro 4,6 difluoronicotinonitrile;

4,5-dichloro 2,6 difiuoronicotinonitrile; 5,6-dichloro-2,4-difluoronicotinonitrile From the crude fluorinated product ofExample 7 there is also distilled off under reduced pressure a fractionboiling at C. at 38 mm. Hg. This fraction is recrystallized from hexaneto recover a product having the appearance of a white shiney Wax. It hasa melting point of approximately 22-25 C., is slightly soluble in waterand highly soluble in acetone and benzene. The carbon chlorine, nitrogenand fluorine contents thereof are 34.2, 34.0, 13.4 and 18.07 percent ascompared to theoretical values of 34.48, 33.93, 13.41 and 18.18 percent,respectively. Nuclear magnetic resonance analysis discloses that theproduct is made up of a mixture of the three isomers appearing in thecaption of this example.

Example 9.2,5,6-trichloro-4-fluoronicotinonitri1e; 2,4,5-trichloro-S-fluoronicotinonitrile; 4,5,6trichloro-Z-fluoronicotinonitrile From the crude fluorinated product ofExample 7 there is further distilled off under reduced pressure afraction boiling at 138-141 C. at 38 mm. Hg. This material isrecrystallized from hexane to recover a white powdery product having amelting point of 70-73 C. It is slightly soluble in water and highlysoluble in acetone and benzene. The carbon, chlorine, nitrogen andfluorine contents thereof are 32.46, 47.38, 12.41 and 7.92 percent ascompared with theoretical values of 31.96, 47.18, 12.43 and 8.43percent, respectively. Nuclear magnetic resonance analysis disclosesthat the product is made up of a mix- Example10.-Tetrafluoronicotinonitrile Tetrachloronicotinonitrile and potassiumfluoride in the ratio of 10 moles of the fluoride to 1 mole of nitrileare placed in a sealed, nickel-lined Inconel bomb. This vessel is heatedfor a period of approximately 10 hours at 350- 400 C. From the reactionmixture so obtained there is distilled under reduced pressure a fractionboiling at 66 C. at 23 mm. Hg. This fraction, which is recovered in 40to 45 percent yield, is a colorless liquid at ambient temperatures. -Itis slightly soluble in water and highly soluble in acetone and benzene.Vapor phase chromatography analysis discloses that the fraction is madeup of 97 percent tetrafluoronicotinonitrile, 2 percent ofmonochlorotrifluoronicotinonitriles and 1 percent of lighter ends.Elemental analysis shows it to contain 41.0, 15.72 and 42.98 percent ofcarbon, nitrogen and fluorine, respectively, as compared withtheoretical values of 40.92, 15.91 and 43.16 percent.

Example 11.Tetrafluoroisonicotinonitrile Tetrachloroisonicotinonitrile(30 grams; 0.124 mole) and potassium fluoride (72 grams; 1.24 moles) areplaced in a sealing nickel-lined Inconel bomb and heated for 12 hours at400 C. The product so obtained is treated with dichloromethane and thesolution so obtained is separated from the remaining insoluble salts.The filtrate is heated to distill ofi the solvent, leaving a solidproduct which is taken up in hexane, norite-treated to remove colorbodies and then recrystallized from solution. The white crystallineproduct so obtained in a yield of 48 percent, has a melting point of65.5-66.5 C. It is slightly soluble in water and highly soluble inacetone and benzene. Vapor phase chromatography analysis discloses it tobe made up of about 99.6 percent of tetrafluoroisonicotinonitrile.Elemental analysis shows it to contain 40.8, 16.1 and 43.1 percent ofcarbon, nitrogen and fluorine, respectively as compared with theoreticalvalues of 40.92, 15.92 and 43.16 percent.

Example 12.3-chloro-2,5,6-trifiuoroisonicotinonitrileTetrachloroisonicotinonitrile and potassium fluoride in a nitrile/fluoride mole ratio of 1:10 are placed in a sealed, nickel-lined Inconelbomb and heated for 8 hours at 300 to 350 C. The product so obtained istreated with dichloromethane and the resulting solution is filtered toremove insoluble salts. The filtrate is heated to drive 01f solvent,leaving a crude fluorinated product which is subjected to repeateddistillation under reduced pressure to finally recover a fractionboiling from 73 to 76 C. at 28 mm. Hg. This product, which has theappearance of a white crystalline material, has a melting point of about25 C. It is slightly soluble in water and highly soluble in acetone andbenzene. Vapor phase chromatography analysis discloses that it is madeup of about 98 percent 3-chloro- 2,5,6-trifluoroisonicotinonitrile.

Example 13 (a) In this operation concentrate compositions in the form ofemulsifiable liquids are prepared by mechanically mixing together 70parts by weight of xylene, parts by weight of an alkylated arylpolyether alcohol (Triton X-100) and 25 parts of each of thecyanofluoropyridine toxicants described in the foregoing Examples 1through 12.

(b) Water-dispersible concentrate compositions are prepared bymechanicaly mixing together 25 parts by weight of each of thecyanofluoropyridine toxicants as described above in Examples 1 through12 with 5 parts by weight of Triton X-100.

(c) Concentrate compositions in the form of wettable powders areprepared by mechanically mixing together 25 parts by weight of each ofthe cyanofluoropyridine toxicants described in Examples 1 through 12, 70parts 10 by weight of fullers earth, 3 parts by weight of an alkyl arylsulfonate (Nacconal NR) and 2 parts by weight of a polymerized sodiumsalt of a substituted benzoid alkyl sulfonic acid (Daxad No. 27).

These compositions are adapted to be dispersed in water to prepareaqueous compositions which have very desirable penetrating and Wettingproperties. The latter aqueous compositions are adapted to be employedto distribute effective concentrations of the toxicant compounds on theseeds as well as in soil.

Example 14 In further operations, acetone solution containing acyanofluoropyridine, as set forth below in Table 1, are employed for thetreatment of sandy loam soil infested with a natural soil fungipopulation including Rhizoctonia solani. In such operations thefungus-infested soil is placed in scalable containers and the acetonesolution of the toxicant is added to each sample in a concentrationappropriate to provide the total soil sample in the container with anamount of either 2.5 or 10 parts by weight of toxicant per million partsby weight of soil. At the same time, checks are prepared by treatingcontainers of the same infested soil with an amount of acetone equal tothat employed in the corresponding test containers. The soil samples arethen sealed and rolled to distribute the toxicant uniformly throughoutthe sample. After an incubation period of 3 days at 25 C., aliquotamounts of each soil sample are taken and diluted in sterile waterblanks. Two drops of each of the resulting soil-water suspensions arethen placed in a petri dish to which 10 milliliters of rose bengal agarare then added. The poured plates are incubated for 5 days at 25 0.,following which they are examined and a count made of the total fungalcolony population on each. The extent to which each toxicant effectedcontrol as compared with the checks, is shown in the following table.

TABLE I.CONTROL OF FUNGAL COLONIES (PERCENT) Example 15 In thisoperation fungi-infected, sandy loam soil samples treated with toxicant,as well as checks, all prepared in the manner described above in Example14 and containing 10, 2.5, 0.6 and 0.16 parts by weight of toxicant permillion parts by weight of soil, are seeded with Panogen treated cottonseeds after the initial 3 day incubation period at 25 C. The samples aremoistened and placed in a room maintained at 17 C. under conditions ofhigh humidity for 10 days to allow the seeds to germinate. At the end ofthis time the resulting seedling plants are evaluated for the presenceor absence of attack by Rhizoctonia solani. The extent to which thetoxicant treated samples and the check survive attack is expressed inthe following table.

TABLE II.CONTROL OF RHIZOCTONIA SOLANI ATTACK ON COTTON SEEDLINGS(PERCENT SURVIVAL) Toxicant concen)tra.-

1 1 Example 16 The operations of Examples 14 and 15 are repeated, butwith a different fungi-infected soil sample, and with othercyanofiuoropyridine toxicants. The results obtained in these tests aregiven in the following table, it being noted that no cotton plantssurvived attack in the check sample of this test series.

The emulsifiable liquid concentrate of Example 13(a) is dispersed inwater to prepare a composition containing 14 pounds oftetrafluoropicolinonitrile per 200 gallons of ultimate mixture. Thelatter composition while under agitation is metered into irrigationwater at the pump outlet at the rate of 4 gallons per 1000 gallons ofthe irrigation water. The water is in a state of turbulent flow as itcomes from the pump, thus providing a thorough mixing of the toxicantcomposition therein. About 3 inches of the irrigation water is appliedto a plot of sandy loam soil of good nutrient content which is heavilyinfested with Pythium spp., Fusarium solani and Rhizoctonia solani. Thetreatment accomplishes a wetting of the soil to a depth of about 2 feetto provide a concentration of about 2.5 parts by weight of the toxicantper million parts by weight of soil. A companion plot is treated in thesame fashion, but without the presence of tetrafluoropicolinonitrile inthe emulsifiable liquid concentrate employed, this plot serving as thecheck. Six weeks following the irrigation, both soil plots are seeded tolima beans. Four weeks after seeding the resulting stand of bean plantsis examined. The plants from the plot treated withtetrafluoropicolinonitrile are found to be growing vigorously andsubstantially free of any evidence of fungal disease. The plants of thecheck plot are found to bear evidence of heavy fungal attack, many ofthe plants being stunted and badly diseased.

Example 18 In this operation a solution of tetrafluoropicolinonitrile inacetone is injected into sandy loam soil at a rate of pounds offungicide per acre foot of soil. The soil is one of good nutrientcontent which is infected with Verticillium, an organism causingvascular wilt of cotton. The acetone solution is injected at a level 6inches deep in the soil in rows 12 inches apart using conventional soilfumigation equipment. The ground is allowed to stand fallow for 3 weeks,during which time the tetrafluoropicolinonitrile diffuses throughout theupper foot of the soil to provide an average concentration therein of2.5 parts by weight of the toxicant per million parts by weight of soil.A similarly infected test plot of the same soil is treated in the samefashion except that the injected acetone is free of any content offungicide. Both plots are then planted to cotton. The plants areexamined near the end of the growing season at a time when the plantsare maturing. Those plants from the untreated, check plot are found tobe wilting despite heavy application of irrigation water, andexamination of their cut stems reveals the presence of a brown-lesionedvascular system. In contrast, the plants in the plot treated withtetrafluoropicolinonitrile are observed to be lush, green and healthy.Their cut stems evidence a healthy, white vascular system.

The expressions growth media and soil are herein employed in theirbroadest sense to be inclusive of all conventional soils as defined inWebsters New International Dictionary, second edition, unabridged,published in 1937 by G. and C. Merriam Company, Springfield, Mass. Thus,the terms refer to any substance or media in which vegetation may takeroot and grow, and are intended to include not only earth but compost,manure, muck, humus, sand and the like, adapted to support plant growth.

The present invention has been particularly described as it relates tosoil fumigation practices for the control of soil-dwelling fungi andbacteria. It should also be pointed out that the cyanofluoropyridinecompounds hereof can also be used as space fumigants to control variousmolds, fungi and bacterial pests which are present on the walls therein.Thus, in the case of graneries or the like good pesticidal action isobtained as a liquid material containing the cyanofiuoropyridinecompound is sprayed or atomized into the atmosphere within the unit. Inthe case of of the storage vessels or on the surface of crops storedpacked fruit, the said compounds can be applied to the inner walls ofthe carton or to the individual papers in which oranges, apples andother fruits are wrapped. The volatility of the present compounds issuch that they provide a long-lasting protective atmosphere in thecontainer and thus control fruit rot.

I claim:

1. Tetrafluoronicotinonitrile.

2. Tetrafiuoropicolinonitrile.

3. 3-chloro-4,5,G-trifluoropicolinonitrile.

4. 3,S-dichloro-4, 6-difiuoropicolinonitrile.

5. 3,5,6-trichloro-4-fluoropicolinonitrile.

References Cited UNITED STATES PATENTS 3,325,503 6/1967 Bimber 260 294.9

ALAN L. ROTMAN, Primary Examiner US. Cl. X.R. 424-263

